Macromolecule Based Conductive Composite Material is sensitive to the change of temperature, and can keep a low resistance at normal temperature, which means the resistance can rise to a very high point to break the circuit when over current or over voltage happens so that the electronic components can be protected. Thus the Macromolecule Based Conductive Composite Material can be connected to the circuit as the current sensor material. This kind of material has been widely used in the circuit protection components.
Macromolecule Based Conductive Composite Material generally is the composition of polymer and conductive filler. Conductive filler is macro evenly distributed in the mentioned Macromolecule Based Materials. Polymer generally is polyolefin and its' copolymer likes polythene or copolymer of ethylene and vinyl acetate, but conductive filler is usually carbon black, metal powder or conducting ceramic powder. Regarding the carbon black as conductive filler, because its' special structure of aggregates and the polar group on the surface can make a good adhesive properties, so the kind of composite material has a good stability in resistance. But carbon black with a limited conductive ability, so it cannot meet the requirement of low resistance. Regarding the Macromolecule Based Conductive Composite Material with conductive filler of mental power, it has a low resistance, but the mental powder is easy to oxidize, so the conductive composite material needs to be packed to protect from the increasing of resistance during the oxidation. However, the size of packed PTC components can't meet the demand of miniaturization. For reaching a low resistance and overcoming the defaults of oxidation, in the industry, metal carbide, metal nitride, metal silicate or metal boride ceramic powder (such as titanium carbide) are tend to be used as the conductive filler of low resistance Macromolecule Based Conductive Composite Material, what's more, this kind of materials have been great developed. But the proportion of metal carbide, metal nitride, metal silicate or metal boride ceramic powder is relatively big in the Macromolecule Based Conductive Composite Material, so the hard processing and poor distribution in polymer led to the resistance can't be further reduced.
Besides, the thickness of PTC components are made by metal carbide, metal nitride, metal silicate or metal boride ceramic powder is limited (like below 1.0 mm, 0.8 mm, 0.6 mm etc.), and the requirements of electrical conductivity can't be met when size be smaller (like 1210,1206,0805,0603 etc.). Thus developing the conductive filler with lower resistivity and better oxidation resistibility is necessary.